One type of device for collecting light and converting it to electricity is a photovoltaic (PV) cell, as used in a solar collector. PV solar collector arrangements are available in two basic varieties, non-concentrating and concentrating with respect to light received. The reference to “concentrating” typically refers to collection optics associated with a PV solar collector arrangement. “Non-concentrating” solar collector arrangements rely on the sun shining directly onto the surfaces of photovoltaic cells that receive light for the purpose of conversion into electricity. Non-concentrating PV solar arrangements typically require large areas of PV devices to collect enough light to produce a suitable amount of electricity. Concentration of light by using light concentrating optics causes collection of light from a specified area and focuses that light into a smaller area, reducing the area of the desired light-collecting PV cells significantly.
Silicon-based PV cells are noted for low light-to-electricity conversion efficiency. However, their relatively low cost makes them suitable for non-concentrating systems. More costly PV devices, such as gallium-arsenide (III-V devices), can be significantly more efficient at converting light to electricity, but are also significantly more expensive than silicon-based devices. The more costly PV devices are thus more suitable for concentrating systems. By making use of light-concentrating collection systems, the size of required PV devices can be significantly reduced, allowing in some cases the use of the higher cost, more efficient, III-V photovoltaic devices.
In addition to light concentration, the PV devices or arrays of PV devices are often fixed to tracking devices that orient the light couplers, or collectors, in an optimal manner for collecting solar energy. The typical relationship is that, the higher the amount of concentration, the higher the degree of accuracy that is needed for a light tracking system. Typically, the cost of the tracking device correlates directly with the required degree of accuracy. Single-axis collectors are often most concerned with tracking in one direction, while dual-axis collectors are often concerned with tracking in two directions. The degree of tracking accuracy on each axis depends on the degree of concentration on each axis.
It would be desirable to provide a method of making an arrangement for collecting (or emitting) light, key parts of which can be performed using automated, mass production techniques. It would further be desirable to provide such a method in which the arrangement for collecting light forms a two-axis concentrator with a medium level of concentration. Since the concentration is divided between two axes, the need for a high level of tracking accuracy is reduced, allowing for lower cost options for tracking equipment.